1. You can open with any range of points. !2-14 is the most popular range nowadays. Others play 12-15 or 16-18
2. You should have no 6 card suits, or good 5 card major suit, and preferably no singleton or two doubletons Guards are required in 3 suits. A guard is Ax; Kx; Qxx; Jxxx
3. Vulnerable take care in opening 1NT with 12 pts.
4. In 4th position 1NT may be opened with 11 pts.
5. Assuming 12-14 is the range, then pass with flat hands of less than 8pts. Bid 2 diamonds, hearts or spades with a 5 card suit and 0-8 pts (‘weakness take-out’)
6. Bid 2NT /3NT with flat hands (may have a 5 card minor suit) and 11-12pts/ or 13+pts.
7. Bid 3 hearts/spades with 12+ pts and a 5 card suit
8. Bid 4 hearts/spades with 12+ pts and a 6 card suit.
9. Use the Stayman convention to find a 4-4 fit in a major suit. A responder’s bid of 2 clubs asks. Opener bids 2 diamonds with no 4 card suit. Otherwise bids heart or spade suit
10. Bid 4 clubs (Gerber convention) to ask for aces over 1NT direct.
11. Open 2NT with 20-22 pts . Responses very like over 1NT but far less points needed
12. You need a combined total of around 26 pts to make 3NT, or less with long suits.